1. Field of the Invention
This invention relates generally to apparatus for processing and curing tobacco leaves and relates particularly to a container which receives a large quantity of randomly oriented green tobacco leaves after which the leaves are secured in position and the container is placed in a tobacco barn for curing the tobacco.
2. Description of the Prior Art
In the past tobacco leaves originally were picked manually and a group of the leaves or a hand were oriented so that the stems were together and the leaves were all disposed in the same direction, after which the stems were lashed together and were hung over a tobacco stick. Subsequently a plurality of rows and columns of sticks were placed in a tobacco barn where they were treated by heat to cure the green tobacco leaves.
In order to reduce the tedious drudgery of tobacco harvesting and curing, tabacco harvesters were developed such as shown by the patents to Long U.S. Pat. Nos. 2,952,370 and 3,215,288 which transport workmen through a tobacco field so that such workmen can prime the tobacco plants manually and convey the leaves upwardly to a platform where other workmen orient the leaves and place the leaves on sticks for curing. In recent years several agricultural colleges and universities have conducted extensive experiments on the bulk curing of tobacco which included tobacco racks that received randomly oriented leaves and after the racks were filled such leaves were fixed in position by pin frames having a plurality of elongated slender rods to hold the tobacco leaves in position when the racks were rotated approximately 90.degree. when placed in a tobacco barn so that warm air could flow upwardly through the tobacco leaves for curing the same. These bulk tobacco racks had a width less than the length of a mature tobacco leaf and were of a size to receive approximately 100 to 150 pounds of green tobacco leaves so that one or two workmen could place the racks in two or three vertically spaced tiers within a barn for curing the leaves.
Some effort has been made to provide a harvester for automatically defoliating some of the leaves of a tobacco plant within a predetermined range above the ground. Some examples of this type of tobacco harvester are the patents to Wilson U.S. Pat. Nos. 2,816,416, 2,834,173 and 3,083,517; Suggs et al. U.S. Pat. No. 2,834,174; Splinter U.S. Pat. No. 3,093,949; Pickett et al. U.S. Pat. No. 3,507,106; and Alphen et al. U.S. Pat. No. 3,695,014.
With the advent of the automatic defoliating tobacco harvester, additional efforts were made to advance the art of handling the tobacco leaves by providing larger racks which could accommodate a substantially increased capacity and which could utilize power equipment such as an overhead hoist for placing the racks within a barn for curing. An example of this type of apparauts is disclosed in the Long U.S. Pat. No. 3,834,137. This structure improved the bulk tobacco rack situation by providing an elongated rack which formed a column of leaves through which warm air passed to cure the leaves.
In the curing of tobacco leaves in large containers or racks, it is especially important to insure the proper airflow throughout the entire curing cycle. When the warm air moves upwardly through the column of leaves, the lowermost leaves cure first by giving up their water content which permits the air to move upwardly through the leaves more easily and progressively cure the upper leaves. However, the drying and shrinking of the lower leaves sometimes tends to open a passage for air through the side of the rack so that the air passes between adjacent racks with the result that some of the upper leaves are not fully treated. Additionally, as the leaves dry and give up their moisture, such leaves have a tendency to bend over or flop as space becomes available due to the shrinkage with the result that the bent leaves block the passage of air so that the air cannot pass through the upper leaves to cure the same.